Accurate Simulation of Surfaces and Interfaces of Face-Centered Cubic Metals Using 12−6 and 9−6 Lennard-Jones Potentials

TLDR

Lennard‑Jones potentials are commonly used in molecular dynamics and Monte Carlo simulations for nonbond interactions. The study introduces 12‑6 and 9‑6 Lennard‑Jones parameters for various face‑centered cubic metals that accurately reproduce densities, surface tensions, interface properties, and mechanical characteristics under ambient conditions. The authors derived these parameters, though the approach omits electronic structure effects and is limited to noncovalent interactions. The new parameters reduce deviations by an order of magnitude, match tight‑binding and embedded atom models in accuracy while being up to a million times cheaper, and enable simulations of metals with biopolymers, surfactants, and nanostructured materials via compatibility with common force fields.

Abstract

Molecular dynamics and Monte Carlo simulations often rely on Lennard-Jones (LJ) potentials for nonbond interactions. We present 12−6 and 9−6 LJ parameters for several face-centered cubic metals (Ag, Al, Au, Cu, Ni, Pb, Pd, Pt) which reproduce densities, surface tensions, interface properties with water and (bio)organic molecules, as well as mechanical properties in quantitative (<0.1%) to good qualitative (25%) agreement with experiment under ambient conditions. Deviations associated with earlier LJ models have been reduced by 1 order of magnitude due to the precise fit of the new models to densities and surface tensions under standard conditions, which also leads to significantly improved results for surface energy anisotropies, interface tensions, and mechanical properties. The performance is comparable to tight-binding and embedded atom models at up to a million times lower computational cost. The models extend classical simulation methods to metals and a variety of interfaces with biopolymers, surfactants, and other nanostructured materials through compatibility with widely used force fields, including AMBER, CHARMM, COMPASS, CVFF, OPLS-AA, and PCFF. Limitations include the neglect of electronic structure effects and the restriction to noncovalent interactions with the metals.